Everyone around Susannah Cahalan was deeply saddened when it looked like the bright, young, up-and-coming journalist began suffering from what appeared to be a severe mental disorder. [Scroll Down For Video]

According to statements she made to a local news agency:

“One moment I would be you know, kind of hysterically happy, and then the next moment I would be despondent. I couldn’t control my emotions,” she said.

Shortly thereafter Cahalan had her first seizure and was hospitalized where her behavior became even more erratic.

“I was, you know kicking and punching nurses, trying to escape. I believed you know, nurses were turning into people, and playing tricks on me. I was seeing things that weren’t there,” she said.

Cahalan also had hallucinations or paintings coming to life and physical abuse by family members who visited her. Some of her doctors were ready to institutionalize her and write her off as another young person who was the victim of an unfortunate mental disorder.

However, one doctor, Souhel Najjar, thought there might be another cause of Cahalan’s erratic behavior. If he was right, her condition was entirely treatable, and biological in nature.

In order to test his theory, he asked Cahalan to draw a clock. The result showed him what the true problem was.

The problem was obviously with the left side of Cahalan’s brain. However, it wasn’t brain damage causing the problem. It was an immune system disorder.

“Disruption of the blood-brain barrier, which is essentially the wall between the periphery and the brain. It prevents harmful substances in the blood to enter into the brain,” Dr. Najjar explained.

With proper drugs to regulate her immune system, Cahalan returned to normal and is now living a completely normal life with no long lasting effects from her ordeal.

“I mean I could have been cognitively impaired and put in a nursing home for the rest of my life, and I’m not. I’m here, and I’m very grateful for that fact,” she said.

Since the ordeal, Cahalan has written a book about her experience entitled, “Brain on Fire.” Dr. Najjar has founded one of the first clinics in the country dedicated to treating similar brain auto-immune diseases.